You've got a couple of other options...
1) Get an alternator for a late Durango. Up around 136A Max output, but you do have to modify the mounting slightly (some grinding is required - but I don't recall how much or what.) Most other later ChryCo trucks should also work - nearly all of them use a Nippondenso alternator (identifiable by the "ND" cast into the rear bearing boss.)
2) Other vendors. Powerman wants to come to mind, and others if you search. Also, you can use the shop I've been using - click the link in my sig, and go to San Jose Generator. (Yes, I know the images are goofy. I'll work on that to-morrow...) Rod does good work, and I've been using him for years (typically, only when I buy a new rig or do a job for someone else have I had to replace his parts. The best warranty is one you don't need - and I've not needed his in the last ten years...)
I think the 1999-up units are "clocked" differently (different relative location of the terminals on the backside WRT the mounting,) which is easily fixable. It's like having to reclock the old Delco SI units - four possible positions, and you can change from one to another in about two minutes with a 5/16" nutdriver. You may want to ask Rod to be sure (if you decide to call him,) but that's mainly what I'm thinking at the moment. I'm working on getting solid information...